Outlining a dramatic sequence of events, President Ricardo Martinelli said the ship was targeted by drug enforcement officials as it approached the Panama Canal and was taken into port, but a search revealed a cargo of far greater concern.

The vessel’s estimated 35-man crew also rioted when police stepped aboard, according to Mr Martinelli, who said the suspicious cargo was found within a massive consignment of sugar.

“The world needs to sit up and take note: you cannot go around shipping undeclared weapons of war through the Panama Canal,” he told Radio Panama listeners.

“We had suspected this ship, which was coming from Cuba and headed to North Korea, might have drugs aboard so it was brought into port for search and inspection,” on the Atlantic coast of the country, he said.